An intake manifold of an engine may be configured to receive gases and provide vacuum to devices external the intake manifold. In one example, fuel vapors accumulated from a vehicle fuel system may be introduced to an intake manifold by way of a port. One system for distributing gases in an intake manifold is described in U.S. Pat. No. 7,299,787. This system provides for a gas introducing pipe that is upstream of a partitioning part, and the intake manifold is bifurcated by the part. Gases flowing from the gas introducing pipe are directed to a first or second group of cylinders by way of the partitioning plate.
The above-mentioned method can also have several disadvantages. Specifically, the intake manifold limits communication between cylinders of different cylinder banks and therefore may interfere with cylinder air flow during some conditions. Further, the intake manifold is more complex than other intake manifolds that have a common collector area between intake manifold runners. Further still, the intake manifold may be less suitable for engines that have a different cylinder firing order (e.g., eight cylinder engines).
The inventors herein have recognized the above-mentioned disadvantages and have developed an intake manifold for improving distribution of gases in an engine intake manifold.
One embodiment of the present description includes an intake manifold, comprising: a non-partitioned intake manifold coupled to an engine and including a common collector to which a plurality of intake runners are coupled; a first port located in said intake manifold and in an air flow path downstream of a throttle body and upstream of said plurality of intake runners; and a protrusion into said intake manifold downstream of said port and upstream of said plurality of intake runners.
By integrating a protrusion into an intake manifold, the intake manifold having a collector common to intake manifold runners, distribution of gases in an intake manifold may be improved without degrading engine performance. For example, a protrusion into an intake manifold at a location downstream of a gas inlet port and upstream of intake manifold runners can improve distribution of gases between the intake manifold runners. As a result, engine air-fuel control may be improved. Further, a protrusion can be designed into the intake manifold such that it has a limited affect on induction of gases into engine cylinders. Thus, engine cylinder air-fuel distribution may be improved without sacrificing engine power.
The present description may provide several advantages. In particular, the approach may improve engine emissions by improving cylinder air-fuel distribution. Further, cylinder air-fuel control may be improved while engine power is substantially unchanged. Further still, a protrusion may be formed in an intake manifold such that no additional components are necessary to improve engine cylinder air-fuel distribution.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.